Method of desiccating.



I. S. MERRELL. METHOD 0F DESIOGATING. APPLIOATON FILED DEG. 8. 1913A Patented M1123, 1915.

2 SHEETS-SHVEBT 1.

Stmme/13 I. S. MERRELL.

METHOD OP DESIGOATING.

APPLICATION FILED DB0. a. 191s.

Patented Mar. 23, 1915.

2 SHEETS-SHEET 2 o u w n Hw w FICE.

mvINe s. MERRELL, or svRacUsEnEw'yonK.

MEM-:ton or'DEsIccATINe.

To allfwhom it may concern.' 1 V Be it known that I, Invllve S. MERRELL, vof

' Syracuse, in the. county of Onondaga and i' not affected.

- 1 lng in 20 State' of New4 York,

which the following is a specification..

VIt luis-heretoforel been proposed to desiccate liquids containing solids (such` as milk,

, lfor example) .by spraying the liquid into a chamber in which a partial vacuum is maintained,thev walls of ed or heat. insulated.y Such methods have proven impracticable because a partial vacuum is an excellent non-conductor of heat rand it has .been found impossible to transmit the requisiteamoun-t fof heat to the sprayed liquid to effect the desiccation in connection with the vacuum. The theory lof desiccata Avacuum is correct because of the relatively low temperaturel at which the drying can becarried out ,with the result that the products of the desiccating process are This -is particularly true in the case of milk and other highly organized substances having a large moisture content, 'such as eggs, because, such substances if subjected ztoair at. high temperatures are a'ected in their qualities .as the air and highheat tends 'to oxidize the product and the result is 'to injure the ivor and keeping quality of the dry product.

The present invention has for-its primary object the supply of the requisite number of heat units -to effect desiccation in a heated chamber in which a high degree of vacuum is maintained. This is accomplished by injecting into the chamber steam which supplies the required heat units and whichis highly superheated so that its reduction in temperature due to the minus pressure vis not suiiicient to cause condensation within the chamber. The walls of the vacuum chamber are maintained at a sufficiently 45' high temperature to preventany condensation u-pon them of the steam under the low pressure maintained in the vacuum chamber by either heating the walls themselves or by heat insulating them. The liquid to be desiccated is sprayed into the chamber in a are subjected tothe fine spray so that al1 portions of the spray heat suppliedjby the superheated steam. L

An apparatus for carrying` out the invention is illustrated in the accompanying drawings in .which' Figure 1, is a vertical section ofthe ap- Specification of Letters Patent. A ppcaton med December s, 19.13.

have invented a newv and ImprovedMethod of Desiccating, of

the chamber beingheatl fthe chamber,

taining the inner wa Patented Mar. a3, i915. Serial No. 805,424.

paratus. Fig. 2, is a horizontal section in vthe plane indicated by the line 2-'2 in Fig.

horizontal section in the lane indicated by the line 3 3 in Fig. 1. 1g. 4, is a detail of the hinge of the door whlch permits the dry. powder .to bewithdrawn'-v f apparatus with sulated walls is shown.

The desicc'ating chamber-A, has double wal-ls B, and @separated so as to insulate and in the 'space between the two walls are located steam coils D, through which steam ows for the purpose vof mainll B, of the desiccating chamber `sufficiently warm to prevent any vcoiidensation on its inner surface. A steam conduit E, extend'sjvertically through the middle of the desiccating chamber and through this steam also flows, This steam .conduit E, forms a Ichannel through which to introduce the super-heated steam supply without having it unduly the chamber at any point.

near its top which is in communication` with a powerful vacuum pump which maintains alpw minus'pressure within,the condenser .and vacuum chamber. 'Thecondensem vac- .uum'chamber and vacuum pumpV are not shown, being of well-known construction.

l. Fig. 3, is a ".llhe lower ,the pressure the better are there- Seite It iS desirable to maintain the .vacuum between twenty to twenty-eight inches of mercury. This may vary, depending upon the materials treated, but the vacuum should never be less than suiiicient to maintain atemp'erature which will not injure the dry product. For instance, skim milk can be dried at one hundred and keighty (180) degrees Fahrenheit without percepti ble injury if removed from theA chamber at frequent intervals. Eggs can be dried with the temperature of one hundred and fifty (150) degrees Fahrenheit if the powder is removed frequently and then cooled. The amount of vacuum used, therefore, depends upon the substance treated. As a general rule, the less the pressure the more etHcient the'action is.

The milk or other liquid to be treated lis sprayed into the vacuum chamber. Conventional spraying nozzles are indicated at G. four being shown, all of which are connected to a supply pipe H. Hydraulic pressure spraying is indicated. The charheat the walls et e desiccating chamber has an outlet F,

acteif hydraulic pressure spraying noz- N, which meshes with the pinion 0, on the zles which are used is illustrated in the operating shaft P, which can be turned in United States Letters Patent of Bevenot any convenient way, as by a crank handle 45 aud de Neveu, No. 1,020,632, March 19, 1912. (not shown). The door L, swings open on a By use of such spraying nozzles an eXceedhollow hinge Q. 4The dry powder removed ingly ne and well distributed spray is pro.- falls down an inclined chute R, to a receivduced. -ing receptacle. The door is jacketed and The central steam conduit contracts downheated, steam being introduced through its 50 wardly and the external walls of the desichollow hinge Q, as shown in Fig. 4. The

locating chamber expand downwardly so as door is held closed tight by the interior to provide increasing area for the spread yvacuum so as to prevent any loss of vacuum. yof the spray as it is projected downwardly AA :shield S, prevents any powder from comfrom the spraying nozzles. Near the lower ying between the central shaft M, of the col- 55 end of the desiccating chamber superheated lector and the interior steam conduit E.

steam is introduced through steam nozzles I. l claim- The steam should be at a very high tem- 1. The method of desiccating organic perature, say in the neighborhood of seven liquids containing a high moisture content hundred degrees Fahrenheit in order to supwhich consists in spraying the liquid inte 6o ply the necessary number of heat units. The a chamber in which a high degree of vacuum globules of the spray vare cooled by the exis maintained, injecting 'into said chamber ceedingly rapid evaporation due to the high highly superheated steam, the temperature temperature of the superheated steam, and 0f the Steam being' Suiciently high So that the heat for this rapid evaporation is taken it will not condense within the chamber at 65 from the superheated steam and used in the'minus pressure maintained-therein, and

turning the liquid of the material to be preventing condensation within the chamdesiccated into vapor. Enough steam is adber by heating the walls thereof. mitted, and at a suiiicient temperature, to 2. The method of desiccating organic as it leaves the chamber at afew degrees which consists in spraying the liquid into above the saturation temperature or the a chamber in which a high degree of vacuum vacuum being carried. is maintained, and injectinginto said chamber The dry powder falls into acollecting superheated steam, the temperature' of the drum J ,.at the bottom of the desiccating steam being suiiiciently high so that it will 75 chamber. This drum has several compartnot condense within the chamber at the ments, as illustrated in Fig. '3, and it; is rominus pressure maintained therein.

tatable so as to bring the different compartln witness whereof, I have hereunto -ments constituted by the partitions K, into Signed my name in the presence of two sub register with a door L, at one side of the scribing witnesses. y chamber. The drum is rotated by any suit- IRVING S. MERRELL. 40 able means. As shown, the central hollow Witnesses:

shaft M, extends below the bottom of the C. L. VILLIAMS, desiccatng chamber, and has a. gear wheel J. S. BARNES.

keep the resulting temperature of the vapor liquids containing a high moisture content 

